Audio-Technica ATH-M50x Professional Studio Monitor Headphones Black hard shell Case Headphones Accessories Bundle. Audio-Technica ATH-M50x Professional Studio Monitor Headphones Black and Case for headphones. As the most critically acclaimed model in the M-Series line, the ATH-M50 is praised by top audio engineers and pro audio reviewers year after year. Now, the ATH-M50x professional monitor headphones feature the same coveted sonic signature, with the added feature of detachable cables. From the large aperture drivers, sound isolating earcup